Abstract
Sequestosome 1 (SQSTM1/p62), long established as a selective autophagy receptor and ubiquitin-binding scaffold, is now recognized as an emerging regulatory hub that integrates signaling, metabolism, and stress adaptation in cancer. Beyond its canonical role in proteostatic cargo degradation, recent advances have revealed that p62 orchestrates nutrient sensing, redox control, innate immune signaling, and metabolic reprogramming through highly dynamic, context-dependent mechanisms. A nascent paradigm emerging from recent studies is that p62 function is specified by a hierarchical post-translational modification (PTM) code, with phosphorylation acting as the primary regulatory layer. Site-specific phosphorylation events-together with modulatory PTMs such as S-acylation, arginine methylation, and O-GlcNAcylation-reshape p62 interaction networks, liquid-liquid phase separation (LLPS) behavior, and signaling output. Through these mechanisms, p62 operates as a sophisticated signal-metabolism interface that couples stress signaling pathways, including NFE2L2/NRF2, AMPK, mTORC1, and NF-κB to the systemic rewiring of glucose, lipid, amino acid, and nucleotide metabolism. Notably, a phosphorylation-dependent positive feedback loop between p62 and AMPK has emerged as a key driver of metabolic plasticity, enabling tumor cells to survive and proliferate under the stringent metabolic stress conditions of the tumor microenvironment. This review integrates recent mechanistic insights into the PTMs, phase behavior, and signaling hub functions of p62, highlighting how these principles manifest in distinct oncogenic contexts, such as lung, prostate, and brain tumors. We further discuss emerging therapeutic strategies that seek to modulate p62-centered assemblies rather than indiscriminately inhibit p62 function. Collectively, these findings position p62 as a phosphorylation-governed oncogenic nexus whose precise manipulation may enable new strategies for context-dependent precision oncology.